Title :
Improvement of electrical and reliability properties of tantalum pentoxide by high-density plasma (HDP) annealing in N2O
Author :
Chang, S.J. ; Lee, J.S. ; Chen, J.F. ; Sun, S.C. ; Liu, C.H. ; Liaw, U.H. ; Huang, B.R.
Author_Institution :
Dept. of Electr. Eng., Nat. Cheng Kung Univ., Tainan, Taiwan
Abstract :
This study aims to improve the electrical characteristics and reliability of low-pressure chemical vapor deposited (LPCVD) tantalum pentoxide (Ta/sub 2/O/sub 5/) films by a new post-deposition annealing technique using high-density plasma (HDP). Experimental results indicate that excited oxygen atoms generated by N/sub 2/O decomposition from HDP annealing can effectively reduce the carbon and hydrogen impurity concentrations and repair the oxygen vacancies in the as-deposited CVD Ta/sub 2/O/sub 5/ film, thereby resulting in a remarkable reduction of the film´s leakage current. Two other post-deposition annealing conditions are compared: HDP O/sub 2/ annealing and conventional plasma O/sub 2/ annealing. The comparison reveals that HDP N/sub 2/O annealing has the lowest leakage current and superior time-dependent dielectric breakdown (TDDB) reliability.
Keywords :
CVD coatings; MIM structures; MOS capacitors; annealing; dielectric thin films; impurities; integrated circuit reliability; leakage currents; nitrogen compounds; plasma materials processing; semiconductor device breakdown; semiconductor device reliability; tantalum compounds; C; C impurity concentration reduction; CMOS technology scaling; H; H impurity concentration reduction; HDP N/sub 2/O annealing; HDP O/sub 2/ annealing; LPCVD Ta/sub 2/O/sub 5/ films; MIM structures; N/sub 2/O; N/sub 2/O decomposition; TDDB reliability; Ta/sub 2/O/sub 5/; chemical vapor deposited films; electrical characteristics; excited O atoms; high-density plasma; leakage current reduction; low-pressure CVD films; metal-insulator-metal structures; oxygen vacancies; planar capacitors; post-deposition annealing technique; reliability characteristics; time-dependent dielectric breakdown reliability; ultrathin gate dielectric film; Annealing; Atomic layer deposition; Chemical vapor deposition; Dielectric breakdown; Electric variables; Hydrogen; Impurities; Leakage current; Plasma chemistry; Plasma properties;
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2002.805029
